Electron-discharge apparatus



Feb. 24. 1925. 1,527,703

' D. C. PRINCE ELECTRON DISCHARGE APPARATUS Filed April 8, 1922 Invent or: David C. rince.

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His Attorney,

f inilis aspecification.

I filament and II 'tion has not I v 35 however, becauseof the fact'that' it, is neces- Q 4 sa'ry in order to roduce any Substantial reduction .in the space'chargedropto-impress Patented Feb. 24, 1925. I

UNITED STATES PATENT" OFFICE.

DAVID c. PRINCE, or scnnnnc'mnr, new Yonx, nssronon 'ro onnnnu. nmc'rnxc COMPANY, A oonrona'rron or mzw Yoa'x.

ELECTRON-DISCHARGE APPARATUS.

To all whom it may concern: I

Be it known that 1; DAVID C. PRINCE, a citizen of the United States, residing at Schenectady, in-the county of Schenectady,

State of New York, have invented certam new and useful Improvements in Electron- Discharge Apparatus, of which the follow.

resent invention relates to electron discharge devices and. more particularly to circuit connections which maybe-employed lwithsuch devices. I i

: The object of my invention isto improve the efiiciency of operatiom-of. electron} dischargedevices.- I I II One of the principal losses incident to the o ration ofanelectron discharge device is t at dueto thespace chargeidro-p. between filament and plate. It has been knownthat 9..this drop in potentialbe'tweenefilament and a plate might be gr atlyreduced'hy the use of a positively charged id .inte -'osed between late. l 'liisf net odiofoperaan employed to" any J extent,

[quite a high positive potential on the grid, and. sea result-the grid itself receives so' 80. many electrons that the-grid losses will more than compensate. for the gain. obtained through" reduction in the space charge drop. The grid losses introduced in this manner, however, are partly due to the .fact that as I 85 the grid potential -is-. inc reased the velocity of the electrons whichreachthe plate will be increased and secondary electrons .will be emitted. These secondary-electrons will' 'be attracted to the grid and-the eifect'will be a. 4o withdrawal ofenerg'y from therplate.circuit.

and absorption ofenergybythe grid circuit.

In carrying my invention into effect If overcome the above disadvantage by providing means for preventing escape of sec 45 o'ndary electrons from I the ate. This means may conveniently 'take t e form of a id interposed between the control grid and fie plate. If, when current is flowing to the plate this extra grid is ma e 'slightlyInega-' ac tive with respect to the plate'no' secondary electrons can escape from the plate and the control id .may be made positive enough to grea yreduee the space charge My invention itself, however, both as to its out circuit organizations where y my.inven-f l auency one.

- the grid 3 and the amount-o this arrangement may be supp iedto 'aicoil vvhat difi'erent way. In this case an inductance 14 is included in circuit between the source of current 9Qand. the plate 4. The.

1022. Serial No. 560,752.

without introducing. compensating grid losses. I 55 -Thenovel features which I believe to be characteristic oflny invention are set forth with particularity in the appended claims.

organization and method of operation will best be understood by reference to the fol- ,j lowing description takenin connection with the accompanying drawin inwhich Figs. 11- and 2 showzdiagranunaticall two difl'ertion maybe carried intoeifect. l

.I have show 'n Fig.-1 ,a'n electron discharge device 1 having the jusual. fila menta cathode2," controlfgrid 3 and plate or an e 4. -An extragrid 5 is interposed between the control grid 3 and the anode 4.

. An oscillating circuit comprisinginductance 1 '6 and capacity 7; is connected-between the" I control grid and anode, an. intermediate point .801? the inductancefi beingconnectedf;.

to the cathode. A source of ener' I 9 conjnected between cathode, and "anode urnislies' .the energy for the oscillating are:

cuit. A chokef18- prevents the high ire from being shortcircuitedrough the-source, 9 and mammal-11pmvwants ghe directjcurrentgfrom .,being ashort 5 circuited throu h inductance d, extra grid 5': is connected to a; point ilidue tance 6 int jermediatethe point 8 end to which the control 1 is-wconnected, The" grid V 5 I will oscillate inpotential. with its-swing can be so adjusted that it will: become just, enoughpositive topermit the-maximum car; rent to flow to the plate and not positive enough to permit it or grid 3 toireceive secondary electrons, emitted from the plate.

High irequency oscillations reduced; by

13 which is coupled to'thef inductance. 6 and supplied from oil 13 to any form of utilization' circuit desired;- I a I Iii the arrangement shown in Fig: 2 the desired results are brought about in a someextra grid 5 is connected to a point in this inductance beyond the plate. connection. 105

with his arrangement the extra grid and 'trol grid for" the plate will oscillate in potential together, but the potential of the extra grid willalways be enough below that of the plate while electrons are passing to the plate to prevent secondary emission. In this case also electrons collected by the .extra grid 5 constitute useful output the same as though they were received by the plate itself. In this case the coil 15 in the'grid circuit may be coupled to the coil 14 in the plate circuit to furnish the necessary feed-back coupling for producin oscillations although the condenser 7 wil ordinarily furnish the only coupling necessary.

The operation of devices such as l have described may also be improved by the use of a black body as anode, that is, an electrode having a surface of such a nature that it doesnot readily emit secondary electrons. This tendency to emit secondary electrons may be reduced by providing a rough surface on the electrode and by the selection of tlie material used for the electrode, copper or nickel, for example, showing much less tendency to emit secondary electrons than "tungsten or molybdenum.

While I have shown and described my invention in connection with systems for the automatic generation of electrical oscillations, my invention is by no means limited to this particular application'as it may be employed to advantage in other cases,'as for example, in the case where oscillations are produced through the relay action of higher positive potential upon said grid duringthe time when it is desired to have current flow to the anode, a secondgrid interposed'between the, first grid and the anode, and meansfor maintainlngthe second grid at a lower potential than the anode during the time when current flows to the anode. v

2'. An electron discharge apparatus comprising a device having an electron emitting cathode, an anode and a control grid, a source of potentialand an oscillating circuit associated with said anode and means for producin oscillations therein, a second grid interposeh between'the control grid and the anode, and means for impressingupon the second grid during periods when current flows'to the anode, a potential less positive than the potential of the anode.

An'electron discharge apparatus comprising a device having an electron emitting cathode, an anode and a control grid, a source of potential connected to said anode, an oscillating circuit associated with said anode and grid in such a way that oscillations will be produced therein by the action of said control grid, :1 second grid interposed between the control grid and the anode, and means for impressing upon the second grid, during periods when current flows to the anode, a potential. less positive than that of the anode.

4. An electron discharge apparatus comprising a device having an electron emitting cathode, an. anode and a control grid, a

source of potential connected to said anode,

an oscillating circuit associated, with said anode and grid in such a way that oscillations will be produced therein by the action of said control grid, a second grid interposed between the control grid and the anode and a connection between said oscillating circuit and sa1d second grid for 1mp-ressing upon the second grid, during pcriods when current flows to the anode, a .potential less positive than that of the anode.

5. The method of operating an electron discharge device having an electron emittin cathode, an anode and two grids interposed between cathode and anode which consists in impressing a positive potential on .the anode to produce a flow of current between cathode and-anode, controlling thefiow of current to produce oscillations by impressing a variable potential upon the grid nearest'the cathode and preventing the escape of secondary electrons from the anode by impressing upon the grid nearest the anode a positive potential lower. than that of the anode.

6. The method of operating an electron discharge device having an electron emitting cathode, an anode and two grids interposed betweencathode and anode, which consists in impressing a positive potential on the anode to produce a flow of current between cathode and anode, varying the potential of the grid nearest the cathode to produce oscillations and causing the potential of the grid nearest the" anode to oscillate with that of one of the other electrodesbut in such a way that when current flows to the anode the potential of the second grid will always be negative with respect to the anode. ,In witness whereof, I have hereunto set by hand this 7th day of April, 1922.

DAVID C. PRINCE, 

